Looping

All loops in Go are variations with the for loops.

Infinite loops

Example:

main.go

package main

import "fmt"

func main() {
    counter := 99

    for {
        fmt.Println(counter)
        counter += 1
    }
}

You can use the break statement to ext a loop:

main.go

package main

import "fmt"

func main() {
    counter := 99

    for {
        fmt.Println(counter)
        counter += 1
        break
    }
}

Loop until condition

Example:

package main

import "fmt"

func main() {
    counter := 1

    for counter < 10 {
        fmt.Println(counter)
        counter++
    }

    fmt.Println("Loop completed")
}

Counter loop

Example:

main.go

package main

import "fmt"

func main() {
    for counter := 0; counter < 10; counter++ {
        fmt.Println(counter)
    }
    fmt.Println("Loop completed")
}

Loop over collections

We can use an array, slice or map for looping over.

Array example:

main.go

package main

import "fmt"

func main() {

    years := [5]int{1999, 2004, 2010, 2014, 2024}

    for index, value := range years {
        fmt.Println(index, value)
    }
    fmt.Println("Loop completed")
}

Map example:

main.go

package main

import "fmt"

func main() {

    type petRecords struct {
        id     int
        animal map[string]string
        age    int
    }

    pets := []petRecords{
        {id: 1, animal: map[string]string{"name": "Mollie", "Breed": "jack russell"}, age: 10},
        {id: 2, animal: map[string]string{"name": "Murphy", "Breed": "terrier"}, age: 8},
    }

    for _, pet := range pets {
        fmt.Println("ID:", pet.id)

        for key, value := range pet.animal {
            fmt.Println(key, ":", value)
        }
        fmt.Println("Age:", pet.age)
        fmt.Println("--------------")
    }
    fmt.Println("Loop completed")
}